AB1219 HOW TO TAILOR THE ANTI-OSTEOPOROSIS TREATMENT IN PATIENTS WITH ADVANCED LIVER DISEASE? VARIATIONS OF RENAL FUNCTION BY CREATININE AND CYSTATIN C
Authors: C. Rodríguez Alvear, N. Buendía Sánchez, E. Garín Cascales, M. D. C. López González, E. Perea Martínez, A. Avilés, I. Calabuig, M. L. Peral, P. Bernabéu, A. Martínez-Sanchis, J. J. Esteve Vives, P. Vela-Casasempere, V. Jovani, M. Andrés
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> A rapid bone loss and an increase in fractures have been described after liver transplantation, warranting focused management. Bisphosphonates are effective antiresorptive agents, but with a limited in patients with significant kidney disease, as the drugs are excreted by urine, accumulating and increasing the risk of adverse events (including at the kidney level). The evaluation of renal function in the patient with cirrhosis can be challenging and may be underestimated by standard methods<sup>[1]</sup>. This issue may impact the choice of the anti-osteoporosis (OP) agent. <h3>Objectives</h3> To compare the variations on bisphosphonate treatment indication across different glomerular filtration rate (GFR) equations in patients with advanced liver disease included in a pre-transplantation study. <h3>Methods</h3> Descriptive cross-sectional study of patients from a tertiary center selected for a multidisciplinary assessment before liver transplantation from February 2019 to December 2022. Sex, age, ethnicity, and serum creatinine and cystatin C (a more sensitive marker than creatinine for the estimation of GFR in patients with cirrhosis<sup>[2]</sup>) levels are collected. The indication for anti-OP treatment is established in the presence of T&lt; -1.0 by densitometry (DXA), vertebral radiographic wedging or history of a fragility fracture. GFR adjusted by creatinine, cystatin C and creatinine-cystatin C was calculated using the online calculation tool MediCalc®. Results are later categorized as below or above 30ml/min<sup>2</sup> (usual cut-off to contraindicate the use of bisphosphonates<sup>[3]</sup>), finally comparing the rate of patients with GFR &lt;30 ml/min across three methods. A descriptive study is presented. Comparison of variables are performed by Fisher's exact test. P-values of &lt;0.05 are considered statistically significant. <h3>Results</h3> A total of 162 patients (75.9% men) were included, all Caucasian, with a mean age of 60 years (SD 7.6) and a mean BMI of 27.9 (SD 4.9). Seventy-six percent (n=120) were candidates to anti-OP therapy, and 68.5% (n=111) ultimately received it (88% bisphosphonates, 11% denosumab, and 1% teriparatide). Three percent (n=5) presented a fragility fracture, and 9.5% (n=17) showed a radiographic vertebral fracture. Fifty-one percent (n=80) had osteopenia and 22.9% (n=36) osteoporosis at DXA scans. Regarding renal function, mean serum levels of creatinine and cystatin C were 0.99 mg/dl (SD 1) and 1.7 mg/L (SD 1), respectively. The mean estimated GFR levels using creatinine, cystatin C and creatinine-cystatin were 87 ml/min (SD 24.8), 49.3 (SD 23.4) and 63.9 (SD 23.3), respectively. The percentage of patients with GFR &lt;30ml/min was 1.9% measured by creatinine, 20.5% calculated by cystatin, and 5.6% calculated by creatinine-cystatin (Figure 1). Differences between rates were statistically significant. In this sense, anti-OP therapy was tailored accordingly in 12 patients (10.9%) with treatment indication, using denosumab instead of bisphosphonates. p 0,008 p &lt;0,001 <h3>Conclusion</h3> In a setting of advanced liver disease candidate to transplantation, renal function estimates significantly varied depending on the GFR equation used, thus largely modifying the rates of patients with contraindication for using bisphosphonates, despite the high fracture risk. Further studies are necessary to establish the best method to assess the renal function in advanced liver disease patients, in order to tailor anti-OP strategies. <h3>References</h3> [1]Skluzacek PA, Szewc RG, Nolan CR, et al. Prediction of GFR in liver transplant candidates. AM J Kidney Dis. 2003;42:1169-76. [2]Ebert N, Bevc S, Bökenkamp A, et al. Assessment of kidney function: clinical indications for measured GFR. Clinical Kidney Journal. 2001;14(8):1861-1870. [3]Riancho JA, Peris P, González-Macías J, et al. Guías de práctica clínica en la osteoporosis postmenopáusica, glucocorticoidea y del varón (actualización 2022). Rev Osteoporos Metab Miner. 2022;14(1):13-33. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.